Single stage refrigeration utilizing holdover means



y 1950 w. A. GRANT 2,515,825

smcu-z STAGE REFRIGERATION UTILIZING HOLD-OVER mums Filed March 16, 1945 2 Sheets-Sheet 1 INVENTOR.

July 18, 1950 w, GRANT 2,515,825

SINGLE STAGE REFRIGERATION UTILIZING HOLD-OVER MEANS Filed March 16, 1945 2 Sheets-Sheet 2 FIG.2

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IN VEN TOR. 404M 4.

BYM ma Patented July 18, 1950 SINGLE STAGE REFRIGERATION UTILIZING HOLDOVER MEANS Walter Adams Grant, Onondaga Township,

Onondaga County, N. Y., assignor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware Application March 16, 1945, Serial No. 583,022 v 7 Claims.

This invention relates to refrigeration and more particularly to the art of obtaining and/or maintaining relatively low temperatures by the utilization of a single refrigeration stage, and in which the refrigeration efiect so obtained and/or maintained may be carried through any desired number of stages to maintain or to decrease the relatively low temperatures first obtained.

Prior to the instant invention, relatively low temperatures have been obtained by the utilization of more than one refrigeration stage. For example, in some prior systems, the condenser of a compressor-condenser-expander system, utilizing carbon dioxide as a refrigerant, has been cooled by the evaporator of a compressor-condenser-expander system utilizing ammonia as a refrigerant. While the example referred to employs the compression type of refrigeration system, the disadvantages inherent in such systems apply equally to absorption systems. These prior systems are expensive and complicated because of the use of a great many elements including the use of two compressors and in some cases the use substantially of two entire refrigeration systems.

It is an object of the instant invention to provide a refrigeration system which will be simple and relatively inexpensiveto manufacture and economical to operate for the production of relatively low temperatures.

It is another object of the instant invention to employ a noval combination of elements served by a single stage of refrigeration for obtaining low temperatures.

It is another object of the instant invention to employ a novel combination of elements served by a single stage of .refrigeration for obtaining low temperatures in which the temperatures so obtained may be maintained or decreased through any desired number of stages.

Other objects and the nature and advantages of the invention will be apparent from the following description to be read in conjunction with the accompanying drawings, wherein:

Figure 1 is a schematic view of a refrigeration system in accordance with the invention; and

Figure 2 is a view similar to Figure 1 of a modified form of the invention.

Referring to Figure l, the compressor serves to compress the refrigerant and discharge it through conduit ll into condenser 12 from which it is passed in liquid form through feed line l3 into the conduit l4, through the expansion valve l5, when valve I6 is closed, and then through the coil Il located within the brine bath [8 in insulated chamber 19. The refrigerant passes from the coil ll into the conduit 20 when the valve 2| is open, then through coil 23 and back through the suction line 24 into compressor III to complete the cycle. The expansion valve I5 is controlled by the bulb T in contact with the suction line 24 at the discharge end of coil 23. It will be understood, if desired, bulb T may be disposed at the exit of coil ll instead of the position chosen.

With the valve I6 closed as described, the coil ll acts an an evaporator and cools the brine l8 within insulated chamber IS. The temperature of the brine I8 will be lowered to a level much cooler than ordinary condenser coolants such as the outside air, or cooling water obtained from a well or municipal system. After the temperature of the brine bath l8 has reached a desired low level, the valve I6 may be opened and valve 2| closed. Expansion valve 22 will now function under control of bulb T in the usual manner. Valves l6 and 2| may be operated manually or automatically as desired. The expansion valves 15 and 22 function automatically, of course, by means of the bulb controls T and T.

The arrangement, upon cooling of the brine to a desiredtemperature is in condition to operate as a low temperature refrigeration system. The hot gaseous refrigerant is conducted along feed line l3 and passes through valve [6 into coil II where it is condensed and possesses a much lower temperature than it had when leaving condenser [2 which, in this stage, is inefiective for condensation. The brine l8 permits a much lower condensing temperature and pressure so that condensation occurs in coil ll. Thus, when the condensed refrigerant passes through the expansion valve 22 to the coil 23, which now acts as an evaporator, refrigerating temperatures will be obtained therein much lower than those produced when conventional condenser cooling means are alone employed.

With the system arranged as described, utilizing coil I! at one time, as during normally idle periods, as an evaporator to cool brine l8, and at another time as a condenser for gaseous refrigerant, such cooled refrigerant when evaporated in a second coil, 23, efiectively produces relatively low temperatures; and this is accomplished'with a simple apparatus requiring a minimum of elements.

It is to be understood that though coils I1 and ranged in a series-parallel relationship with the use of appropriate valves, 50 that when coil I1 I is used as an evaporator to cool brine I8, coil 23 may be completely by-passed,.and the gas from coil I'I proceeds directly tothe compressor. Then, when coil I1 is used as a condenser for cooling the refrigerant passing therethroughithat is, giving off heat to the already cooled brine I8), it will be in series with coil 23 which evaporator.

Also, if it is desired to employ coils I1 and 23 I in series, the refrigerant after cooling the brine,

maybe used in coil 23 for cooling air or gases flowing across coil 23, but the temperature of 1 coil 23 in such event will be higher than when the brine is used for condensing the refrigerant and 'coil 23 used as the primary evaporator.

The duration of the low temperature effect may be of any desired length dependent upon the quantity of brine stored in chamber I9 and hence the duration of the storage cycle.

then acts as an When it is desired to obtain comparatively lower temperatures in area I25, then expansion valve II will be closed, valve 6 opened,.expansionvalve I22 opened and valve I2I closed so that coil I23 will become a primaryevaporator. It will, be understood that suitable fans or blowers may be provided for circulating air or gases over {coils I23 and I21. When coil I23 is used as the It will be understood the system described above is not limitedto the stages of refrigeration described since additionalstages may be obtained by adding additional coils and brine tanks. In otherwords, a suitable series of brine tanks may be arranged to pass the refrigeration effect from one to the other until a desired low temperature is reached and/or maintained.

The system described in connection with Figure 1 serves to operate the evaporator 23 at relatively low temperatures intermittently since time periods are required for cooling the brine at which times coil 23 #does not function as a low temperature evaporator. When it is desired to utilize this system in such a manner as to make available relatively low temperature conditions at desired intervals, a system may be used corresponding tothat shown in Figure 2. In Figure 2, compressor I I0 discharges refrigerant gas through line I I I whence it passes through condenser 2.. The liquefied. refrigerant then passes through feed lineI'I3, into line H4, and through expansion valve H5, valve I16 being closed; then through the coil lI'l located within brine bath 8 in insulated chamber H9. The refrigerant leaving coil III then passesthrough the line I20, the valveI2I 'being open and expane sion valve I22 closed; through the coil I23 within the area to be conditioned I25, and back to compressor IIO through suction line I24 to complete the cycle. Area I25 is the one which requires a relatively low temperature.

So far the system is the same as. in Fig. 1 and may be operated in the same way. However,

provision is here made for supplying the cold ill) pnimary evaporator, pum P may be shut down. While this will cut off refrigeration service in area I23, it will enable lower temperatures to be obtained in coil I23. Thus the system may be employed with maximum effect in a. restaurant, for example, where light loads between meal hours are encountered in the restaurant proper (area I28) duning which time freezer space (area I25) may effectively beserved; I

Valves H5, H6, I2I and I22'may be manually controlled if desired, and automatic controls of different types will suggest themselves to those skilled in the art for cutting in and out of service responsive to changing load conditions or prescribedsettings. 4 I

Applicant therefore provides a simple yet ef- :fective arrangement for providing low temperatures while utilizing compress'orand evaporator- [1. A refrigeration system. forobtaining rela tively low temperatures comprising a compressor,

a condenser, a first coil, and a second coil, said compressor. condenserand two collsbeing connected in a closed circuit; afirst' expansion valve in said circuit-associated with the inlet of said first 'coil; a second expansion valve, associated with the inlet .of said second coil;- a first bypass conduit connected in said circultfor byep i iug said first expansion valve; means for'shutting off and opening s id. first by-pass conduit; va second by- I pass conduit connected insaidcircuit for b'y-passing saidsecond expansion valve; second means for shutting oii and opening said second by-Dass conduit; and athermal hold-over disposed in heat exchange relationwith said first cell; said circuit being so arrangedthat when said first expansion 1 valve is in operation; and the flrst'by-pas con brine IIB from chamber H9 through line I26- into coil I21 within an area to be conditioned I28; A pump P circulatesthebrine' from chamher 9 to coil I21 and back to chamber H9 through return line I29. Thermostat or equi-' valent'control T located within the brine IIB" controls valves'lii, H6, I22, -and ,I2I insuch a manner that'when thetemperature'of the brine II8 goes above apredetermined level, the expansion valve H5 will be opened;.the valve H6 closed,

opened sothat the coil II.I';will become anevap v orator to cool the brine-to ste peratu e below tained within area] ond by-passconduitis" closed 'bysaidsecondmeans whereby therefrigerant in saidfirst coil willbe-condensedqsubse'quent to its leavingthe l a compressor andfsaid second coil 'willact as a' relatively low-temperatureevaporator to produce ambient atmcspnere about said'second coil...

duit is closed'bysaid means; saidfsecond expansion valve/does notfunction; and the second bypass conduit is open'whereby saidflrst coll acts as an evaporatorto' pro-cool: said, thermal hold- 1 7 1 over; said circuit being further-"arranged so that first expansio'n-valveydoesnot functiongsaid'sec- I ond expansionvalvexis in operation and the secrelatively low temperatures in the 2. The structure recited in claim. 1, said coil and said second coil being connected in series.

mall.

'lThestructurerecited in'claim 1,-said.theri hold-eves F comprising; a brine; within tively low temperatures comprising a compressor, a condenser, a combined heat absorbing and heat rejecting element, a cold holdover, a low temperature evaporator, means for first utilizing said combined heat absorbing and heat rejecting element as an evaporator for removing heat from said cold holdover, and then, as a heat rejector after a desired temperature is obtained in said cold holdover, to reject heat to said cold holdover for condensing the refrigerant therewithin prior to its passage to the low temperature evaporator, whereby relatively low ambient temperatures will be obtained about said low temperature evaporator, said means including a line connecting the condenser with said element, expansion meansin said line, a by-pass line about the expansion means, a valve for closing and opening the bypass, a third line connecting said element and the low temperature evaporator, second expansion means in the third line, a second by-pass line about the second expansion means, and a second valve for closing and opening the second by-pass.

5. A refrigeration system for obtaining certain low temperatures intermittently, and other low temperatures substantially constantly, comprising a compressor, a condenser, a combined heat absorbing and rejection. element, a brine tank arranged about said heat absorbing and heat rejecting element, a relatively low, temperature evaporator, means for first utilizing said combined heat absorbing and heat rejecting element as an evaporator to remove heat from said brine tank and then as a heat rejector after a desired temperature is obtained in said cold holdover to transfer heat to said brine tank for condensing the refrigerant therewithin prior to its passage to the relatively low temperature evaporator whereby relatively low ambient temperatures will be maintained about said relatively low temperature evaporator said means including a line connecting the condenser with said element, expansion means in said line, a by-pass line about the expansion means, a valve for closing and opening the by-pass, a third line connecting said element and the low temperature evaporator, second expansion means in the third line, a second by-pass line about the second expansion means and a second valve for closing and opening the second by-pass, a cooling element connected in thermal association with said brine tank, means for circulating brine through said cooling element and means for maintaining said cooling element below a predetermined temperature level.

6. In a refrigeration system for obtaining relatively low temperatures, the combination of a compressor, a condenser for volatile refrigerant,

a first coil, a brine chamber in which said first coil is disposed, a second coil, said compressor, condenser and coils being connected in a closed circuit; an expansion valve disposed in said circuit associated with the inlet to said first coil, a by-Dass conduit connected in said circuit for by-passing said expansion valve, first means for opening and closing said by-pass conduit; a second expansion valve disposed in said circuit associated with the inlet to said second coil, a second by-pass conduit connected in said circuit for by-passing said second expansion valve, and second means for opening and closing said second by-pass conduit; said circuit being so arranged that when the first expansion valve i in operation and the first by-pass conduit is closed by said first means, said second expansion valve does not function and the second by-pass conduit is open whereby said first coil serves as an evaporator to pre-cool the brine in said brine chamber; said circuit being further arranged to provide that when said first by-pass conduit is open and the first expansion valve does not function, said second expansion valve is in operation and the second by-pass conduit is closed by said second means, whereby the refrigerant in said first coil will be condensed and said second coil will act as a relatively low temperature evaporator to produce relatively low temperatures in the ambient atmosphere about said second coil.

'7. The method of obtaining relatively low temperatures comprising compressing a volatile refrigerant, condensing said volatile refrigerant, expanding the volatile refrigerant to refrigerate a precooling medium, then after said precooling medium has attained a desired temperature utilizing said precooling medium to condense volatile refrigerant, evaporating the refrigerant condensed by said precooling medium to obtain a relatively low temperature in air circulated in heat exchange relation therewith, and utilizing said precooling medium to cool a space at a relatively higher temperature level.

WALTER, ADAMS GRANT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,836,090 Shipman Dec. 15, 1931 2,101,953 Oman Dec. 14, 1937 2,319,502 Gould May 18, 1943 FOREIGN PATENTS Number Country Date 440,306 Great Britain -1- 1935 

